Artificial tooth-crown



(No ModeL) M. L. LOGAN. ARTIFICIAL TOOTH cnowu.

No. 310,294. Patented Jan. 6, 1885.

WITN ESSE UNITED STATES PAT NT OFFICE.

MARSHALL L. LOGAN, OF TYRONE, ASSIGNOR TO THE S. S. \VHITE DENTAL MANUFACTURING COMPANY, OF PHILADELPHIA, PENNSYLVANIA.

ARTIFICIAL TOOTH-CROWN.

EPECIPICATION forming part of Letters Patent No. 310,294, dated January 6, 1885.

Application filed January 15, 8. 4. (.\'0 model.)

.To all whom it may concern:

Be it known that I, MARsHALL L. LOGAN, of Tyrone, in the county of Blair and State of Pennsylvania, have invented a certain new and useful Improvement in Artificial Tooth- Orowns, of which the following is a specification.

My invention relates to artificial toothcrowns more especially designed for application to natural tooth-roots remaining in the mouth, but may be used in the construction of other artificial dentures; and its object is to provide an improved and cheap crown which may be readily, firmly, and durably secured to the natural root or to a plate, and which, when so secured, will present a natural appearance, while being capable of virtually the same service as a wholly natural tooth.

In the accompanying drawings I have shown my improved crown and its application to a natural root.

In said drawings, Figure 1 is a side view of my improved crown for incisor teeth, the crown being shown as secured in place upon an incisor-tooth root. Fig. 2 is a vertical section thereof. through the improved incisor-crown detached, and Fig. 4 is a bottom or basal plan thereof. Figs. 5 and 6 are an elevation and a section of a modification ot the crown.

The tooth-root A is prepared in any of the well-known ways, by grinding or cutting the defective or decayed natural crown down to the neck of the tooth or to the level of the gum, and the root is hollowed out as usual, to provide space for an anchoring or securing pin, B, projecting from the base or floor ol" the artificial crown O, the space in the root being furthermore sufficiently extensive to receive the filling material D, usually an amalgam or a similar plastic filling. The artificial crown C is preferably made wholly of porcelain, to imitate natural teeth in shape, size, form, and shade, this 1naterial-to wit, porcelainbeing a well-known material in the art for the manufacture of artificial teeth and crowns, and having been demonstrated by the most extensive use to have great superiority over other materials for the manufacture of artificial teeth and crowns. The base of the crown is provided with an opening or recess,

Fig. 3 is a vertical section (1, extending into the body of the crown, and being undercut or shouldered around its edges, as at c, or provided with retaining pits, grooves, or other retaining-points for the engagement of the filling material D, which, in connection with the anchoringpost B, hereinafter to be particularly described, unites the crown and root together. This recess or cavity 0, however, need not be undercut, and I do not wish to limit my invention to such a construction; so, also, the crowns may be mounted upon plates for artificial dentures. Projecting centrally, substantially, and in the longitudinal line of the crown from its base and through the basal opening is the anchoring or retain ing pin or post B, this pin being firmly united to the crown during the operation of baking the porcelain. This pin B is shown in Figs. 2 and 3 as a plain cylindrical pin; but it may be provided at the end, which is baked in the porcelain, with an enlargement or head, and at its lower end or shank with a similar retaining head or enlargement, as shown in Fig. 6, for example; or said shank may be barbed or otherwise given a form to be securely engaged by the filling material D, which unites the root and crown or plate and crown to get-her.

I do not, of course, limit myself to the pQClv liar shape of the anchoring post or pin, as it may be fiat, triangular, or oval, as well as round or of other shape, and may be headed or enlarged at one or both ends, or may be plain; or the sides of the pin or post may be barbed or pitted or otherwise constructed.

In applying the crown to the natural root the hole or opening in the root is first filled with plastic material. which preferably extends above the end of the root in sufficient mass to fill the basal opening in the crown, the crown being fitted upon the root with the shank of the anchoring-pin inserted into said retaining material in the root. The surplus retaining material when the crown is being pressed to place upon the root is squeezed out at the edges, while the upperl portion thereof flows into the basal opening of the crownand engages its retaining shoulder or groove, and said material when set or. hardened obviously affords a continuous, firm, and close connection between the root and crown, and effectually prevents any entrance of moisture between the joints. The edges of the crown and root are, of course,

prior to the application of the crown, coincrown having a basal opening to receive the filling material, and an anchoring post or pin which is first fitted in the root and afterward united to the crown by the hardening or setting of a cement or amalgam.

As has been said, my improved crown is a porcelain crown having an enlarged basal opening and a projecting anchoring post or pin baked into the crown in the process of making it.

Iclaim as my invention A porcelain tooth-crown provided with an enlarged basal opening coextensive, substantially, with the entire base of the crown and with a pin projecting beyond saidbase, said pin extending through said opening into the body of the crown and around the end of which the said crown is baked or burned in the process of manufacture, substantially as described.

In testimony whereof I have hereunto snb scribed my name this 19th day of January 5 A. D. 1884.

MARSHALL L. LOGAN. lVitnesses:

D. 'l. CALDWELL, \V. H. SoULLIN. 

